Objective To investigate the lipid-lowering and liver protective effects of β-nicotinamide mononucleotide (NMN) on hyperlipidemic model rats. Methods The 50 male SD rats were randomly divided into a normal group, a model group and low, medium and high dose groups of NMN (10, 50, 250 mg/kg), with 10 rats in each group. The normal group was given maintenance feed, while the other groups were given high-fat feed to establish a high-fat model. After successful modeling, gastric lavage intervention was performed in each group. After 5 weeks of intervention, serum biochemical indicators and blood lipids were measured, including total cholesterol (TC), triglycerides (TG), low density lipoprotein cholesterol (LDL-c), high densitylipoprotein cholesterol (HDL-c) levels, glucose (GLU), alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatinine (CREA) levels, combined with pathological observation of liver histological changes and nonalcoholic fattyliver disease activity score (NAS) of liver tissues was evaluated. Results Compared with the normal group, the body weight of the model group rats increased significantly, and the levels of TG, TC, LDL-c and ALT (P<0.01) in their serum increased significantly, AST and ALP levels significantly increased (P<0.05) The level of HDL-c (P<0.05) decreased significantly, while GLU and CREA showed no significant changes. Compared with the model group, the TG, TC and ALT levels in the low and medium dose groups were significantly reduced (P<0.05), the LDL-c in the medium dose group was significantly reduced (P<0.01). The TG, AST and ALT content in the high-dose group was significantly reduced (P<0.05). However, TC and LDL-c were significantly reduced (P<0.01); there was no significant difference in HDL-c, ALP, GLU and CREA. Compared with the model group, the low, medium, and high dose groups improved hepatic steatosis and inflammatory infiltration in rats, and the total score of NAS in the medium and high dose groups was reduced and showed statistical significance. Conclusion NMN can reduce the blood lipid levels in hyperlipidemic SD rats and has a certain protective effect on the liver.

Objective To establish a method for determination of total arsenic in food by inductively coupled plasma mass spectrometry. Methods The 0.3 g of the biological component standard substances, namely rice and spinach, were weighed and digested using a microwave digestion instrument. Then, the collision mode was adopted to reduce the interference of mass spectrometry. The non-mass spectrometry interference was corrected by the internal standard. Acetic acid, isopropanol, methanol and ethanol were selected as sensitizers, and the concentration of the added sensitizers was adjusted and optimized. The response value of arsenic was determined by inductively coupled plasma mass spectrometry. Results The highest arsenic response value was observed at 6% isopropanol content. The established method was applied to analyze certified reference materials and real food samples. The measured values of certified reference materials all fell within their certified values and uncertainty ranges, with relative errors below 2.0%. The limit of detection for total arsenic was 0.0016 mg/kg. Conclusion This method demonstrates straightforward operation, good precision, high accuracy, and a low limit of detection, making it suitable as a reliable analytical approach for determining total arsenic content in various food samples.

Objective To understand the pollution level of pesticide residues in vegetables sold in Tibet. Methods In August 2024, 50 vegetable samples (eggplant, celery, lettuce, cucumber, broccoli) were randomly collected from 5 cities in the Tibet Autonomous Region. The 43 kinds of pesticide residues were detected by liquid chromatography-tandem mass spectrometry, and a risk assessment dietary exposure was conducted. Results The detection rate of pesticides in 50 vegetable samples was 6.05%, with a total of 14 kinds of pesticides detected, with the highest detection rate being enoxymorpholine. The pesticide exceedance rate in 50 vegetable samples was 0.326%, and a total of 3 kinds of exceedance pesticides were detected, with the highest exceedance rate being avermectin. Pesticide residues had been detected in 5 cities, with the exception of Naqu City, the other 4 cities had exceeded the standard. The chronic ingestion risk values of pesticides detected in 5 kinds of vegetables were: Eggplant (0.001-0.023 mg/kg), celery (0.006-3.665 mg/kg), lettuce (0.001-0.697 mg/kg), cucumber (0.001-0.188 mg/kg) and broccoli (0.002-0.463 mg/kg). Conclusion Different levels of pesticide residues can still be detected in 50 vegetables sold in Tibet, but the residue level is low; the chronic intake risk values of 5 kinds of vegetables are all far below 100%, and the health risks of residents ingesting pesticide residues in vegetables through dietary pathways are within an acceptable range.

Objective To evaluate the acute toxicity and genetic toxicity of γ-polyglutamic acid (γ-PGA). Methods Acute toxicity was evaluated by oral gavage of γ-PGA at 10000 mg/(kg·bw) to rats and mice using the limit test method, with observations of toxic signs and mortality; the 30 hour double gavage method followed by microscopic examination to quantify the frequency of micronucleated polychromatic erythrocytes in mouse bone marrow was employed to detect the micronucleus induction of γ-PGA; the plate incorporation method was utilized to enumerate revertant colonies of Salmonella typhimurium strains (TA97a, TA98, TA100, TA102 and TA1535) to assess the mutagenic potential of γ-PGA; a continuous 5 day gavage followed by microscopic analysis was conducted to analyze the number and frequency of chromosomal structural aberrations in mouse spermatocytes to evaluate the chromosomal aberration induction of γ-PGA. Results The maximum tolerated dose (MTD) of γ-PGA via acute oral administration to both male and female mice and rats was greater than 10000 mg/(kg·bw). At a dose of 5000 mg/(kg·bw), γ-PGA did not significantly increase micronucleated polychromatic erythrocytes in the bone marrow of either male or female mice (P>0.05), nor did it induce chromosomal aberrations in primary spermatocytes of mice (P>0.05). Additionally, at a dose of 5000 μg per plate, no significant mutagenic activity was detected in the standard tested strains (TA97a, TA98, TA100, TA102 and TA1535), regardless of S₉ activation. Conclusion Under the experimental conditions of this study, γ-PGA is classified as practically non-toxic and non-genotoxic, providing a toxicological basis for its development and application in the food industry.

Patulin is a secondary metabolite produced by fungi such as Penicillium and Aspergillus species, widely present in fruits and their products. Due to its multiple toxicities, it poses a severe threat to food safety. The thiol group in sulfhydryl compounds exhibits chemical reactivity and demonstrates a significant role in the detection and removal of patulin. Through Michael addition reactions, thiol compounds specifically bind to the β-lactone ring of patulin, substantially reducing its toxicity and concentration. Furthermore, functionalized thiol materials, such as thiol-modified nanoparticles and aerogels, demonstrate excellent adsorption performance and separation efficiency, providing efficient, economical and environmentally friendly solutions for ensuring food safety. This paper reviewed the research progress and underlying mechanisms of thiol compounds in the detection and removal of patulin, aiming to provide theoretical references for future research and applications in food safety.

Objective To optimize the ultrasonic-assisted extraction process of proanthocyanidins from Polygonum aviculare by response surface method, to obtain the best extraction conditions. Methods The main factors affecting the extraction amount were investigated through single-factor experiments. Based on the results of the single-factor experiments, the Box-Behnken design and response surface methodology were used to optimize the single factors, including the volume fraction of ethanol, ultrasonic time, and solid-liquid ratio, which had an impact on the extraction amount of proanthocyanidins from Polygonum aviculare. The optimal extraction process conditions were obtained. Results The optimized results of the optimal process conditions for ultrasonic-assisted extraction of proanthocyanidins from Polygonum aviculare were as follows: The ultrasonic time was 34 min, the volume fraction of ethanol was 65%, and the solid-liquid ratio was 1:46 (g:mL). Under these process conditions, the final extraction amount of proanthocyanidins reached 2.18%, which was consistent with the model validation value of 2.12%. Conclusion This study shows that the process condition parameters optimized by the response surface methodology are effective and feasible. The response surface methodology is successfully applied to optimize the extraction parameters of ultrasonic-assisted extraction of proanthocyanidins from Polygonum aviculare, providing a research basis for the later promotion and application of proanthocyanidins from Polygonum aviculare.

Objective To identify flavor compounds in Douzhir and Ma Tofu and analyze their characteristic components based on purge and trap-gas chromatography/mass spectrometry (PT-GC/MS) combined with the national institute of standards and technology (NIST) database. Methods Weigh 2.0 g of sample into a 40 mL brown spiral sample bottle, add 10 mL of experimental water and a tetrafluoroethylene magnetic stirrer, heat the sample at 40 ℃, and analyze it by PT-GC/MS. Results A total of 260 kinds of flavor compounds were identified across 34 batches, including sulfur-containing compounds, alcohols, aldehydes, ketones, esters, etc. Raw and cooked Douzhir exhibited significantly higher relative abundances of sulfur-containing compounds compared to Ma Tofu, which showed greater diversity but lower similarity in flavor profiles. These identification data could to some extent reflect sensory evaluation results, but there was a possibility that some flavor compounds might be more prominent or interfered with by other odors. In addition, this study used principal component analysis (PCA) method to identify the overall distribution of samples and deviations from samples, and attempted to analyze the reasons for deviations. Further, using orthogonal partial least squares discriminant analysis (OPLS-DA), based on the screening conditions [P<0.05, variable importance in the projection (VIP)>1], 31 kinds of characteristic flavor compounds of raw and cooked Douzhir were selected, which could be used for the differentiation and identification of raw and cooked Douzhir. Conclusion The study confirms that PT-GC/MS combined with multivariate statistical method can effectively analyze the flavor compounds of Douzhir and Ma Tofu, screen the characteristic compounds, and provide a basis for the subsequent optimization and improvement of product flavor.

Objective To investigate multiple mycotoxin contamination and patterns in Triticum aestivum L. samples from China in 2023 and 2024. Methods A total of 248 Triticum aestivum L. samples were randomly collected from the main Triticum aestivum L.-producing areas of the country (2023: 145; 2024: 103). Simultaneously, liquid chromatography-tandem mass spectrometry (LC-MS/MS) and enzyme linked immunosorbent assay (ELISA) was used to determine the content of various mycotoxins in Triticum aestivum L.. Results The total exceeding rate of mycotoxin contamination in 248 Triticum aestivum L. was 98.0%. The positivity rate for these mycotoxins ranged from 0.4% to 87.1%, with average contamination levels ranging from 0.4 to 604.3 μg/kg. Positive mean values for regulated toxins such as deoxynivalenol and zearalenone, and emerging toxins such as alternariol and enniatins in Triticum aestivum L. were lower in 2024 than in 2023. In addition, the results of zearalenone ELISA (2023: 91.5%, 88.5 μg/kg; 2024: 92.2%,79.4 μg/kg) had relatively large differencey from those of LC-MS/MS (2023: 28.7%, 17.7 μg/kg; 2024: 29.1%, 5.0 μg/kg). Conclusion Triticum aestivum L. mycotoxin contamination is less severe in 2024 than in 2023. Higher levels of contamination with deoxynivalenol-3-glucoside, alternariol and beauvericin are also found in Triticum aestivum L..

Objective To establish a non-derivatized extraction method for the simultaneous determination of chlorthal-diacid, dalapon and trysben in tea by liquid chromatography-tandem mass spectrometry (LC-MS/MS) combined with hydrophile-lipophile balance (HLB) clean-up. Methods Tea samples were extracted by 20 mL of 1% acetic acid in water and 10 mL of methylene chloride; clean-up by HLB (300 mg/3 mL) filtration. Separation of the target analytes was achieved on an octadecylsilane (C₁₈) chromatographic column, and quantitation was performed by LC-MS/MS in negative ion mode. Results The 3 kinds of herbicides were effectively separated on the C₁₈ column with good linearity in the range of 0.01-2.00 μg/mL (r²>0.997). At 4 spiked levels of 0.05, 0.25, 0.50 and 1.00 mg/kg, the average recoveries of the 3 kinds of pesticides in the blank matrix of tea ranged from 71.1% to 119.2%, with the relative standard deviations between 3.3% and 18.3%. The limits of detection were ranged from 0.002-0.009 mg/kg, and the limits of quantitation were ranged from 0.008-0.029 mg/kg of the 3 kinds of herbicides. Conclusion The developed method offers a simple and rapid pretreatment procedure, eliminating the need for derivatization. It is friendly to the inspectors and the environment, and can be used as a method for large-scale detection of chlorthal-diacid, dalapon and trysben residues in tea.

Objective To establish a method for the simultaneous determination of 26 kinds of veterinary drug residues in 3 categories including sulfonamide, quinolones and tetracyclines based on duck meat by ultra performance liquid chromatography-tandem triple quadrupole mass spectrometry. Methods The 0.1% formic acid acetonitrile extraction was used, QuEChERS purification agent was used to remove impurities. After nitrogen blowing in a 45 ℃ water bath to near dryness, the mixture was diluted with 0.1% formic acid water acetonitrile (1:1, V:V) and analyzed qualitatively and quantitatively using ultra performance liquid chromatography-tandem triple quadrupole mass spectrometry. Results The 26 kinds of veterinary drugs showed good linearity in the range of 2.0-300.0 ng/mL (r²≥0.9996), the limits of detection were 0.28-6.02 μg/kg, the limits of quantification were 11.28-15.03 μg/kg. The average recovery rates of 26 kinds of veterinary drugs at different concentration levels (5.0, 50.0, 300.0 μg/kg) were 75.08%-112.35% (n=15), and the relative standard deviations (RSDs) were 1.25%-7.88% (n=15). Conclusion This method features simple pretreatment operations, high efficiency, and low consumption of reagents and materials. It is suitable for the preliminary screening and detection of 26 kinds of veterinary drug residues in 3 categories for large quantities of duck meat samples.